Experience in making critical decisions under conditions of ambiguity, high risk, and time pressure comprise an essential component of nursing expertise. This aspect of expertise, though recognized as important, is difficult to gain access to or to communicate to others. Nonetheless, if highly experienced nurses' mental models could be described and shared with other health care providers, quality of communication, efficiency, and speed of acclimation to the hospital environment could be greatly increased. The proposed study is directed toward demonstrating the feasibility of using a Critical Decision method for developing descriptive models of nurses' decision making. We plan to examine the contextual factors, situational assessment, decision processes, and strategies involved in the decision making of highly proficient nurses. Information obtained in Critical Decision interviews will be summarized in a Nursing Decision Profile and the validity and utility of the Profile evaluated by both highly experienced and novice nurses. The proposed research will extend findings regarding decision making in natural tasks and settings. It also has direct and significant implications for key areas of nursing including training, organizational efficiency, specific problem solving, and acclimation to the hospital environment.